I think Christopher Nolan is the best all-around modern director. His movies are huge critical hits: most of them are in the IMDb Top 250 (most directors would be happy to have one film up there). His films are also huge box-office hits, which means that the audience, not just movie nerds, like his movies.

I think the distribution for films is bimodal, one huge peak for box-office/mass-appeal hits, and another smaller peak for critical hits/film-nerd-appeal hits.

Nolan would be right in the center between these two distributions: he pushes cinema forward while keeping it accessible to all.